Heretofore, numerous corrosion inhibiting compositions have been utilized to inhibit the buildup of scale or corrosion on metal objects in an aqueous system.
For example, U.S. Pat. No. 3,505,238 to Liddell relates to salts of amino methylene phosphonates which are added to saline water alone or in combination with one or more anti-foam agents, water soluble polymers, tannins, lignins, and deaerating materials to inhibit the deposition of scale on water evaporators.
U.S. Pat. No. 3,351,558 to Zimmerman relates to detergent compositions containing organic phosphonate corrosion inhibitors and various other additives.
U.S. Pat. No. 3,600,470 to Lewis relates to the production of hydroxy substituted phosphonates which are produced by the reaction of a halohydrin with an aliphatic or aromatic phosphite.
U.S. Pat. No. 3,639,645 to Miller relates to scale inhibiting compositions such as an alkylene polyamino methylene phosphonic acid. A polycarboxylic acid can also be utilized.
U.S. Pat. No. 3,699,047 to Petrey relates to a corrosion inhibitor for metals contained in an aqueous medium containing a divalent metal ion, a chelating agent, and a modified lignosulfonate polymeric material.
U.S. Pat. No. 3,666,664 to Lorenc et al. relates to a composition for inhibiting scale formation on metal objects containing nitrilotriacetic acid and a specific organophosphonate.
U.S. Pat. No. 3,738,806 to Feiler relates to a method for inhibiting corrosion of metals in contact with an aqueous medium utilizing a complex made from an organo-phosphorus ligand and a metal ion such as zinc, etc. A lignosulfite can be utilized as a binder.
U.S. Pat. No. 3,751,372 to Zecher relates to a corrosion inhibitor for metals in an aqueous medium which contain various polyphosphates or a phosphorylated polyols and organophosphonic acids. Citric acid can be utilized as an additive.
U.S. Pat. No. 3,806,459 to Petrey et al. relates to a composition for the inhibition of scale on metallic surfaces in contact with water wherein the composition contains a phosphonic acid and an aminoacetic acid.
U.S. Pat. No. 3,901,651 to Benner et al. relates to the inhibition of metal parts in an aqueous system by utilizing a composition containing a water soluble phosphone or phosphine, a water soluble sulfonated lignin and a water soluble cation.
U.S. Pat. No. 3,925,245 to Harris relates to a composition for inhibiting the corrosion of metal surfaces in contact with an aqueous medium containing an inorganic nitrite and an amino alkyl-phosphonic acid.
U.S. Pat. No. 4,026,815 to Kallfass et al. relates to a composition for inhibiting corrosion of metals in an aqueous medium utilizing a phosphonocarboxylic acid and various other compounds including a lignin sulfonate.
U.S. Pat. No. 4,033,896 to Mitchell et al. relates to corrosion inhibitors along with various additives such as sequestering agents.
U.S. Pat. No. 4,052,160 to Cook et al. relates to a method of treating an aqueous system to inhibit the corrosion of metals in contact therewith utilizing a phosphonic acid and other additives including precipitating agents such as, sequestering agents.
U.S. Pat. No. 4,138,353 to Lipinski relates to a corrosion inhibiting composition wherein effective amounts of citric acid or other compounds are utilized in association with an amino methylene phosphonic acid or a derivative thereof.
U.S. Pat. No. 4,209,487 to Hogue relates to 1,2-ethane diphosphonates in association with various compounds including tannins, lignins, lignin sulfonates, and the like.
U.S. Pat. No. 4,217,216 to Lipinski relates to corrosion inhibiting compounds containing an effective amount of at least one aminomethylene phosphonic acid.
U.S. Pat. No. 4,246,030 to Lipinski relates to corrosion inhibiting compositions containing a water soluble carboxylic acid, an amino alkylene phosphonic acid, and other inhibitors such as azoles and the like.
U.S. Pat. No. 4,303,546 to Waegerle relates to corrosion inhibiting compounds containing hydroxy alkane diphosphonic acids and the like which can be utilized in association with polyhydroxy acids such as gluconic acid.
U.S. Pat. No. 4,437,898 to Drosdziok et al. relates to corrosion inhibiting compositions containing a plurality of compounds including various complexed phosphonic acids.
U.S. Pat. No. 4,446,028 to Becker relates to corrosion inhibiting compounds containing a water soluble isopropenylphosphonic acid copolymer composition.
U.S. Pat. No. 4,606,890 to Fisk relates to a process for inhibiting corrosion on metal surfaces in contact with water by treating said surfaces with 2-hydroxy-phosphonoacetic acid.
The above patents do not recognize the use of a sequestrant in association with a carboxylated phosphonic acid.